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United States Patent |
5,306,082
|
Karlin
,   et al.
|
April 26, 1994
|
Appliance doors and panels
Abstract
An appliance door particularly suited for use as a refrigerator or freezer
door includes a hollow, blow molded door slab, and a food storage shell or
casing projecting from one wall of the slab. The parts forming the shell
are prepared in a first step, e.g., by blow molding, and then are
removably mounted as inserts in registering recesses formed in the bottom
of the cavity of one of two plates or sections forming the mold for the
door slab. The two mold sections are then closed over a tubular, plastic
parison which is then inflated to form in the mold the hollow door slab,
portions of one wall of which mold over and around a series of male
projections which extend into the mold cavity from the mold inserts, thus
causing the shell to be molded to and to project from the slab upon
subsequent opening of the mold sections and removal of the slab therefrom.
Additional mold inserts may be used to create expansion grooves in the
slab wall which supports the shell, and the opposite or outer wall of the
slab may be curved to reduce undesirable effects of thermal bow.
Inventors:
|
Karlin; James (28 Clarkes Crossing, Fairport, NY 14450);
Bank; David G. (4801 Reservoir Rd., Geneseo, NY 14454)
|
Appl. No.:
|
897765 |
Filed:
|
June 12, 1992 |
Current U.S. Class: |
312/405; 312/405.1; 312/406.1; 312/408 |
Intern'l Class: |
F25D 011/00 |
Field of Search: |
29/530
264/515,516
312/405.1,406,406.1,406.2,407,407.1,408,405
|
References Cited
U.S. Patent Documents
2839347 | Jun., 1958 | Strub | 312/405.
|
3331648 | Jul., 1967 | Petkwitz et al. | 312/405.
|
3702355 | Nov., 1972 | Hayden.
| |
4779939 | Oct., 1988 | Stich | 312/405.
|
4952347 | Aug., 1990 | Kasugai.
| |
5100213 | Mar., 1992 | Vandarakis et al. | 312/405.
|
Foreign Patent Documents |
42863 | Sep., 1985 | JP.
| |
42865 | Sep., 1985 | JP.
| |
42866 | Sep., 1985 | JP.
| |
42867 | Sep., 1985 | JP.
| |
42868 | Sep., 1985 | JP.
| |
Other References
Engineered Blow Molding Design, by Lincoln J. Alvord, 1989, pp. 1-13,
published by G.E. Plastics.
|
Primary Examiner: Gorski; Joseph M.
Attorney, Agent or Firm: Shlesinger, Fitzsimmons & Shlesinger
Claims
We claim:
1. An appliance door, comprising
a hollow, plastic, molded door slab having a pair of vertically spaced
upper and lower end walls, respectively, and a pair of spaced inner and
outer walls, respectively, extending between said end walls,
a storage shell projecting from the side of said inner wall of said slab
remote from said outer wall thereof,
said shell comprising a pair of laterally spaced side walls extending
vertically of said slab, and a pair of vertically spaced upper and lower
end walls, respectively, connected at opposite ends thereof to said side
walls and extending transversely therebetween,
each of said walls of said shell having thereon at least one projection
molded in a registering recess in said inner wall of said slab thereby to
fix said walls of said shell to said slab,
a pair of vertically spaced pivot pin bushings anchored coaxially of each
other in one of said pairs of vertically spaced end walls for use in
mounting the door for pivotal movement on an appliance, and into and out
of a closed position in which said shell faces the interior of said
appliance, and
expansion means formed in said door slab to compensate for any thermal bow
caused by temperature differentials between the walls of said door slab
and the interior of an appliance upon which the slab is mounted.
2. The appliance door as defined in claim 1, wherein said pivot pin
bushings are anchored in said upper and lower end walls, respectively, of
said door slab.
3. The appliance door as defined in claim 1, wherein said pivot pin
bushings are anchored in said upper and lower end walls, respectively, of
said shell.
4. The appliance door as defined in claim 1, including
a shelf mounted in said shell between said upper and lower end walls
thereof, and extending transversely between the side walls of said shell,
and
said shelf having on opposite ends thereof projections which are seated in
registering grooves formed in said spaced side walls of said shell.
5. The appliance door as defined in claim 4, wherein
said shelf has thereon at least one further projection embedded in a
registering recess in said inner wall of said slab operatively to fix said
shelf to said door slab, and
each of said recesses in said inner wall of said slab is formed by molding
registering portions of said inner wall around said projections on said
walls of said shell, and around said further projections on said shelf,
whereby each of said recesses in said inner wall has the same
configuration as the projection embedded therein.
6. The appliance as defined in claim 4, wherein
said shelf has thereon at least one further projection slidably seated in a
registering recess in said inner wall of said door slab, and
said projections on said opposite ends of said shelf are slidable
selectively through openings formed in the ends of said registering
grooves remote from said slab, whereby said shelf is removably mounted in
said shell between said side walls thereof.
7. The appliance door as defined in claim 1, wherein said expansion means
comprises a shallow groove formed in and around said inner wall of said
door slab adjacent the periphery thereof.
8. The appliance door as defined in claim 7, including a resilient gasket
secured to said inner wall of said door slab around and in overlapping
relation to said groove.
9. The appliance door as defined in claim 1, wherein said outer wall of
said door slab is non-planar.
10. The appliance door as defined in claim 1, wherein said outer wall of
said door slab is curved slightly outwardly from said inner wall about an
axis extending parallel to the common axis of said pivot pin bushings and
substantially medially of the sides of said slab.
11. The appliance door as defined in claim 1, wherein
each of said pivot pin bushings comprises a socket member having therein a
circular recess for accomodating a pivot pin, and
an integral flange is attached to and surrounds each of said socket members
and is embedded in said door slab adjacent one corner thereof operatively
to support socket its attached member with said recess therein facing
outwardly of said slab.
12. The appliance door as defined in claim 1, wherein said expansion means
comprise a plurality of spaced, parallel grooves formed in said inner wall
of said slab and extending transversely of said side walls of said shell.
13. The appliance door as defined in claim 1, including insulation material
disposed in and substantially filling the space between said inner and
outer walls of said door slab.
Description
BACKGROUND OF THE INVENTION
This invention relates to improved appliance doors and panels, and more
particularly to an improved method of manufacturing such doors and panels.
Even more particularly this invention relates to a two-step manufacturing
procedure for producing a blow molded plastic refrigerator door assembly
that is specially designed to reduce the impact thereon of thermal bow.
As used hereinafter, thermal bow refers to that characteristic common to
most of the plastic articles referred to herein--i.e., the tendency of
plastic to move away from cold and toward heat. A refrigerator/freezer
presents an extreme temperature difference of 60.degree. to 90.degree. F.
from inside to outside, and within approximately two inches of distance.
In a horizontal plane, where gravity is a contributor, a minimal
temperature deviant will exhibit the bow condition. Previous attempts to
create a plastic solution have not succeeded in managing the thermal bow
characteristics. In normal conditions a plastic refrigerator door would
distort outwardly, overcoming formed structural details intended to
stiffen the part. Several features integrated into the new design
methodology described below are believed to manage the thermal bow
condition.
The conventional method of constructing refrigerator doors includes
providing a stamped and formed metal shell (exterior door panel) which is
adjoined to a vacuum formed plastic shell (interior door panel), either by
enclosing the perimeter of the plastic shell with formed flanges on the
metal shell, or by a plurality of retaining strips and screws. A gasket
may also be attached to the interior shell by means of the same retaining
strips and screws. Then, according to the former, a foaming agent that
solidifies to become a rigid insulating material may be blown in-between
the interior and exterior shells, or according to the latter, a rigid foam
insulation may be inserted therebetween prior to their connection to
provide additional structural support. Finally, the door handle and other
decorative features are attached to the exterior shell, and pivot pin
bushings are inserted into the four corners on the top and bottom ends of
the exterior shell to allow reversible hanging of the door on a
refrigerator. The metal shell, due to its rigidity and conductivity, does
not visually exhibit the characteristic of thermal bow. There are,
however, several problems using conventional refrigerator door design
details for a plastics solution such as, first, the lack of structural and
design features fully effectively to manage the thermal effects resulting
from the internal/external temperature difference; second, the use of
rigid insulation results in a direct transfer of thermal effects from the
interior surface to the exterior surface; and third, the number of steps
required to assemble the door.
Extrusion blow molding using special plastic resins, such as Acrylonitrile
Butadiene Styrene (ABS), Polycarbonate (PC), Polyphenylene Oxide (PPO) and
Polyvinyl Chloride (PVC), is a manufacturing process which is
characterized by the extrusion of a tubular, molten plastic parison
between opposing mold plates prior to their closure. Once the mold plates
are closed the force of air introduced by a blow pin into the center of
the captured parison causes the molten plastic to expand and to conform to
the mold cavities and to any incongruities or inserts projecting from the
confronting internal faces thereof. Efforts to use a one-step blow molding
process for refrigerator or freezer door manufacture have previously been
unsuccessful due to the failure of such doors adequately to manage the
above-noted thermal bow problems, and material distribution problems
caused by disproportionate blow ratio conditions on opposing sides of the
pinch line.
It is therefore an object of this invention to provide a two-step
manufacturing process and design details for the construction of an
appliance door, the structural integrity of which resists the effects of
thermal bow.
Another object of this invention is to provide an improved, hollow
refrigerator or freezer door containing insulation types alternative to
rigid foam, which enhance structural considerations and thermal bow
management of such doors.
Another object of this invention is to provide a refrigerator door, the
construction of which utilizes more efficient manufacturing procedures and
allows for improved quality, thereby rendering such refrigerator doors
more economical to produce.
Another object of this invention is to illustrate that a simplified mold
design for appliance doors is possible without the need for inclusion of
sophisticated slide or cam action, thereby reducing initial and on-going
production costs.
Yet another object of this invention is to provide a novel refrigerator
door and manufacturing method therefor which permits product line
distinction, design options and model changes to be effected on a
selective basis without the need for total retooling.
Other objects of this invention will become apparent hereinafter from the
specification and the recital of the appended claims, particularly when
considered in conjunction with the accompanying drawings.
SUMMARY OF THE INVENTION
Each door produced according to the present invention is manufactured in
two distinct steps where, first, the elements which are to form the
interior shell or casing (walls, shelves, shelf supports, etc.) are
produced during an independent operation, for example a first blow molding
operation, and second, some or all of the interior elements of the first
step are utilized as mold inserts which become physically attached to the
outer, hollow door slab as it is formed during a second, blow molding
operation. Each completed door has an inner shell or casing having top and
bottom walls, respectively, and two upright side walls, portions of which
walls are retained within a molded door slab, and a number of shelves or
trays which extend between the side walls.
According to one embodiment the shelves of a refrigerator door are used as
mold inserts so that selected portions thereof which are exposed to the
mold cavity are permanently retained in place due to collective
encapsulation thereof in the molded door slab. According to a second
embodiment, the inner wall of the door slab and the side walls are
modified to accommodate adjustably removable shelves and/or bins.
Regardless of the embodiment, structural design considerations and
insulation techniques and materials are provided for the door so that it
will be capable of managing thermal bow, thereby rendering the door
resistant to physical deformation and distortion. These structural designs
may comprise parallel grooves in the interior door surface, and/or an
expansion groove extending about the perimeter of the door surface, and/or
a non-planar exterior door surface. A plastic design solution provides the
industry with user features not possible with the conventional
manufacturing procedures and materials. Also, the manufacturing
efficiencies achievable and marketing potentials possible are unique to
plastic.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a refrigerator door and the
various parts thereof made according to a first embodiment of the present
invention;
FIGS. 2A and 2B are elevational and cross sectional views, respectively, of
one of the two mold inserts or dams which ultimately form the two
shelf-supporting side walls of this door;
FIGS. 3A and 3B are plan and end elevational views, respectively, of one of
the mold inserts which forms the shelves or trays that are disposed to
extend between the side walls of this door;
FIGS. 4A and 4B are plan and end elevational views, respectively, of a mold
insert which forms the bridge or top wall which extends between the upper
ends of the side walls of this door;
FIGS. 5A and 5B are front and side elevational views, respectively of one
of the retainer bars that are used in conjunction with the shelves after
the door has been molded;
FIG. 6 is a greatly enlarged fragmentary perspective view of a mold insert
which forms one of four pivot pin bushings which are mounted in the four
corners of this door;
FIGS. 7A is a perspective view, and 7B and 7C are enlarged longitudinal
sectional views of blow molding apparatus employed to produce this first
embodiment, FIGS. 7A and 7B showing the two mold plates of the apparatus
as they appear in their open positions prior to the molding step, and FIG.
7C showing the closed mold plates and how the parison conforms to the mold
cavity and exposed surfaces of the inserts;
FIG. 8 is a cross sectional view taken along line 8--8 in FIG. 7C looking
generally in the direction of the arrows;
FIGS. 9A and 9B are front elevational and cross sectional views,
respectively, of this door as it appears after it has been molded and
insulated, the door being shown with portions thereof cut away, and with
an optional expansion groove located adjacent its perimeter; and
FIGS. 10A and 10B are front and side elevational views, respectively, of a
molded and insulated refrigerator door made in accordance with a second
embodiment of this invention with parts thereof cut away and shown in
section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings by numerals of reference, and first to FIG.
1, 20 denotes generally a refrigerator door comprising a blow molded door
slab 21, from one side of which project side walls 22, shelves 24, and an
upper wall 26, and in opposite ends of which are secured pivot pin
bushings 28. Door 20 is manufactured according to two successive steps.
First, its door side walls 22 (FIGS. 1 and 2A, 2B), its shelves or trays
24 (FIGS. 1 and 3A, 3B), the lowermost of which also forms a bottom wall
of the door, and its upper wall or bridge 26 (FIGS. 1 and 4A, 4B) are
independently produced in any conventional manner, but preferably by a
first blow molding operation (not illustrated). Secondly, the side walls,
trays, bridge and pivot pin bushings 28 (FIGS. 1 and 6) are mounted, as
described hereinafter, in one of two mold plates in such manner that
selected portions thereof are exposed to or face upon the mold cavity,
whereby such exposed portions are encapsulated in the inner wall 23 of
door slab 21 upon the formation of the slab during a final blow molding
operation (FIGS. 7A, 7B, 7C and 8).
More specifically, door 20 comprises a pair of elongate, laterally spaced
side walls or door dams 22 (only one of which is illustrated in detail in
FIGS. 2A and 2B), each of which is the mirror image of the other. In the
preferred embodiment each wall 22 is a hollow, blow molded product having
along the back edge thereof a plurality of spaced, projections 30 which
are dovetail shaped in cross section, and are disposed to become
encapsulated in the slab wall 23 during a subsequent or second blow
molding step. Each wall 22 has a front edge thereon which is characterized
by a plurality of extensions 34. Each wall 22 also has a planar outer side
32 (FIG. 2B), and an inner side 33 having therein a pair of spaced,
horizontally disposed, elongate recesses 35 which open on the back edge of
the wall adjacent projections 30, and a pair of vertically disposed,
elongate recesses 36 which open on the upper edges of extension 34.
Adjacent its upper end, the inner side 33 of each wall 22 also has therein
a horizontally disposed recess 37 which opens on the back edge thereof
adjacent one of the projections 30. Both recess 35 and recess 37 are
intended to receive portions of trays 24 and bridge 26, respectively, as
noted hereinafter.
Each hollow, blow molded tray 24 (FIGS. 3A and 3B) has a horizontally
disposed inner edge having thereon a plurality of spaced projections 40
similar to projections 30, and likewise disposed to become encapsulated in
the inner wall 23 of door slab 21 during a subsequent blow molding step.
Projecting from each lateral edge of each tray 24 is an elongate detent
41, each of which is disposed to engage in a recess 35 in a side wall 22.
The preferably hollow, blow molded top bridge 26 also has on its inner
edge a plurality of spaced projections 46 which are similar to projections
30 and 40, and likewise disposed to become encapsulated in the inner wall
23 of door slab 21 during a subsequent blow molding step. Also projecting
from each lateral edge thereof is an elongate detent 47, each of which is
disposed to engage in a recess 37 in a side wall 22.
For each shelf or tray 24, a retainer 42 is necessary to provide support
for any foodstuff which may eventually be placed thereon. Retainer 42 has
thereon a top surface with flanges 43 projecting from opposite lateral
ends thereof, whereby flanges 43 are disposed to be seated on the upper
side of extensions 34 on walls 22. Also projecting from the lateral ends
thereof are detents 44, which are disposed simultaneously to engage
recesses 36 while flanges 43 are seated on extensions 34.
A consideration for each door 20 is the presence of four pivot pin bushings
28 (FIGS. 1 and 6), one of which is mounted in each of the four corners of
the door so that it may be hingedly connected to a refrigerator for either
left or right-handed operation. Each bushing 28, which by way of example
may be formed from metal, comprises a semicircular upper wall 52 having
therein a central recess or capsule 53 disposed to accommodate a pivot pin
(not shown), and a rear wall 55 which is bent perpendicular to the upper
wall. The entire perimeter of each bushing 28 has thereon inwardly bent
flanges 56 disposed to become captured by the door slab 21 during its
formation.
The mold for producing slab 21 comprises two mold plates 60 and 61 (FIGS.
7A, 7B, 7C and 8). Plate 61, which forms the exterior or outer half of
door slab 21, has therein a smooth, curved cavity 62 that forms a
non-planar, arched surface S (FIGS. 1 and 9B) on the exterior of door 20.
In comparison to a flat surface, surface S provides greater rigidity to
the door structure, thereby contributing to the ability of the door
structurally to manage the forces of the thermal load placed thereon and
to minimize any distortion thereof. Plate 60, which forms the inner half
of slab 21, has in the bottom of its cavity a plurality of recesses 22',
24' and 26' (FIGS. 7B, 7C and 8) which conform to and removably
accommodate those portions of walls 22, trays 24 and bridge 26 which
ultimately are to project outwardly from wall 23 of the molded door slab
21. Also at this time the projections 41 at the ends of shelves 24 are
seated in the registering recess 35 in end walls 22, as shown for example
in FIG. 8, and projections 47 of wall 26 are seated in grooves 37 of the
end walls. With walls 22, shelves 24 and wall 26 thus prepositioned as
mold inserts within mold plate 60, the male interlocking projections 30,
40 and 46 on walls 22, trays 24 and bridge 26, respectively, project
outwardly from mold plate 60 toward plate 61 and into the mold cavity
which will subsequently be occupied by the inner wall 23 of door slab 21.
To complete the set-up of plate 60, the four pivot pin bushings 28 (FIG. 6)
are mounted in recesses in the corners of the rectangular mold cavity in
plate 60 with the flanges 56 thereon projecting outwardly generally
towards plate 61. Plate 60 also has thereon, adjacent the perimeter of its
cavity an arrangement of core pins which are disposed to produce in the
inner wall 23 of door slab 21 a like arrangement of molded core bosses 64.
These bosses provide pockets for accommodating and retaining individual
screws or the like, which are used thereafter (see FIG. 1) to anchor a
gasket 65 against wall 23 beneath metal retaining strips 66, or the like.
As an option, and for the purpose of forming and opening 25 (FIG. 1),
which extends completely through the finished door 20 for accommodating a
liquid or ice dispenser or the like (not illustrated), a pair of
confronting, generally rectangularly shaped insert blocks 87 and 88 (FIGS.
7B, 7C and 8) are secured each at one end to the bottom of the cavity in
the mold plates 60 and 61, respectively, and project at their opposite
ends into confronting, registering engagement with each other when the
mold plates are closed, as shown in FIGS. 7C and 8. Once plate 60 has been
completely set-up with its interior door inserts prepositioned in its
cavity, the subsequent blow molding operation may commence.
This blow mold step is effected by causing a hollow, molten parison P to be
extruded between the open plates 60 and 61 (FIGS. 7A and 7B), after which
the plates are closed (FIGS. 7C and 8) to capture the parison P between
opposing mold plates 60 and 61. The parison is subsequently inflated with
air, which causes the plastic material forming the parison to conform with
the internal mold surfaces and exposed portions of the mold inserts,
thereby forming involutions 67 about the protruding male interlocking
projections 30, 40 and 46, and flanges 56. The involutions 67 in the slab
wall 23 form encapsulations around the male interlocking projections 30,
40, and 46, and flanges 56, thereby effectively integrating parts 22, 24,
26 and 28 with the door slab 21, and forming therefrom an inner shell or
casing for supporting food on the inside of door 20. Once this blow
molding operation is complete and the plastic has cooled, the door slab 21
may be removed from between the mold plates so that retainers 42 may be
inserted in recesses 36 of the side walls, and finishing details such as
placement of the gasket 65 and the handle 69 (FIG. 1) may be effected.
After completion of the foregoing molding operation, and in order more
efficiently to manage thermal bow, a non-rigid insulating material M (FIG.
9B) is inserted into the space located between the curved outer wall and
the inner wall 23 of door 20, and functions to dampen and minimize the
transfer of thermal bow from the interior surface to the exterior surface.
Optionally, the non-rigid insulating material M may be either a blown foam
agent, loose fiberglass particles, etc.
A structural feature, which can be used in door 20 in combination with the
above-noted non-rigid insulation M to contribute to greater physical and
dimensional stability of the door, is the presence of a uniform depth
expansion groove 68 (FIGS. 9A and 9B), which may be formed around the
inner wall 23 of door slab 21 adjacent the perimeter thereof. Groove 68
extends around the outside of the inner shell or casing defined by the
walls 22, 26 and the lowermost tray 24, and inwardly of the array of
bosses 64. Such an expansion groove 68 will further contribute to the
structural integrity of the refrigerator door 20 by absorbing and
redistributing the effects of thermal bow placed upon the interior door
surface, thereby allowing the door to resist any distortion or warping of
the exterior surface. Cosmetically, the groove 68 may be hidden by the
gasket 65, which would be attached adjacent thereto and in overlapping
relation. Placement of gasket 65 in such a position will not only conceal
the groove 68, but also reduce the amount of dust or other organic matter
which may settle and collect therein.
Referring no to the embodiment shown in FIGS. 10A and 10B, 70 generally
denotes a refrigerator door having a hollow door slab 71 containing
insulation M, and disposed adjustably to accommodate adjacent its inner
wall 73 a plurality of removable trays 74 or the like, only one of which
is shown fragmentarily in each of FIGS. 10A and 10B. Door 70, which has a
flat or planar rather than curved outer wall, is also manufactured
according to a two-step operation whereby, first, the door side walls 72,
top and bottom walls 80 which are to form the inner shell or casing, and
the trays 74 are independently produced utilizing, preferably, blow
molding operations. Secondly, the door side walls 72 and top and bottom
walls 80 are securely retained on wall 73 upon the formation of the door
slab 71 during the subsequent blow molding operation. Unlike the first
embodiment, the side walls 72 and top and bottom walls 80 are retained on
wall 73 immediately adjacent and about the perimeter thereof, which
essentially provides a larger inner shell or casing, and consequently
greater storage area.
A pair of elongate, hollow door side walls 72 are similarly required for
each refrigerator door 70, and again, each such wall is the mirror image
of the other. Each wall 72 has along the back edge thereof a plurality of
spaced, interlocking projections 78 which appear dovetailed in cross
section, and which are disposed to become encapsulated in wall 73 of door
slab 71 during the blow molding operation. Each wall 72 has in its inner
side a plurality a equispaced, horizontally disposed, elongate recesses
75, each of which communicates at its outer end with an inclined slot 76
that extends upwardly and opens onto the outer or front edge 77 of each
end wall. Also, side walls 72 have on their inner sides, respectively,
adjacent the upper and lower ends thereof, horizontally disposed recesses
79 which are disposed to receive top and bottom walls 80 as noted
hereinafter.
Each top and bottom wall 80 generally resembles the top wall 26 of the
first embodiment. Although slightly thicker than top wall 26, top and
bottom walls 80 have along their back edges a plurality of interlocking
projections 81 which are similar to projections 78 and likewise are
disposed to become encapsulated in wall 73 of door slab 71 during the blow
molding operation. Also, walls 80 have extending from their opposed
lateral ends elongate detents 82 which engage in recesses 79 on side walls
72, thereby securing together walls 72 and 80 while they are retained by
door slab 71.
Each tray 74 generally resembles the trays 24 of the previous embodiment.
However, the back or inner edge 74' of each tray 74 is tapered downwardly
from the upper surface to the bottom surface thereof in order to
facilitate easy removal of tray 74 from door 70 as noted hereinafter.
Similar to trays 24 of the previous embodiment, trays 74 have projecting
from their opposite lateral ends elongate detents 84, which are disposed
to be seated removably and slidably within recesses 75 in opposing side
walls 72.
Registering with the inner ends of each pair of recesses 75 in side walls
72 is a horizontally disposed groove 93, which is formed in the interior
surface 73 of door slab 71 by the tapered inner edges 74' of the tray
inserts 74 during the blow molding operation. The grooves 93 extend
between the door walls 72 and conform to the shape of the tapered edges
74' of trays 74. Each groove 93 appears generally Z-shaped in cross
section and comprises a flat, horizontal shelf 94 (FIG. 10B) which
projects outwardly slightly beyond the interior surface 73 before tapering
downwardly towards the interior surface, and an inclined roof 95 which
tapers into the door slab 71 where it joins shelf 94. Trays 74 are
releasably seated in door 70 between door walls 72 by sliding their back
edges into groove 93 and their opposed lateral detents 84 into slots 76
and subsequently recesses 75, respectively.
Another difference between the first embodiment and the present embodiment
is the placement of the pivot pin bushings. Rather than being located in
the upper and lower corners of the door slab 71, they are mounted in the
inner shell or casing. Specifically the bushings 28 in this second
embodiment are placed in the upper and lower corners of the side walls 72
adjacent the edges thereof remote from the inner wall 73 of slab 71.
Consequently, the axis of rotation for the door according to the second
embodiment extends through one of the side walls 72 rather than extending
through the door slab itself. Due to the location of the side, top and
bottom walls and the placement of the pivot pin bushings, a gasket 65'
must be placed about the perimeter of the collective wall structure.
Relocation of trays 74 may be effected simply by raising the front edge of
a tray upwardly and away from the door 70 such that opposed detents 84
enter slots 76, whereby continued upward and outward movement will release
a tray from door 70. Once a tray has been removed, and the desired new
location has been found, detents 84 are reinserted into a pair of opposing
slots 76, and the tray is slidably pushed downwardly and inwardly to seat
the tray in its new position.
In addition to the horizontal arrangement of grooves 93, other structural
design features may also be added to the door 70. Such design features are
displayed in the figures dedicated to the first embodiment and may
include, instead of a planar outer wall, the arching of the exterior door
wall, and/or an expansion groove located in the interior door surface
adjacent the perimeter thereof. In the second embodiment, the expansion
groove would have to be located adjacent the perimeter of the door, yet
interior to the side, top and bottom walls. Each of these structural
features will greatly contribute to the ability of the door to manage
thermal bow and resist any outward distortion of the interior and exterior
door surfaces. Also, the greater the number of such features which are
present, then greater is the resistance to the thermally induced
distortion.
In addition to the use of trays 74 in connection with the second
embodiment, removable storage bins may also be employed using a similar
array of detents to engage recesses 75 and groove 93. Also, variations of
the flange and recess mechanism may also be employed in lieu of providing
shelves and/or bins which are easily releasably secured to the door
interior. Another variation to this mechanism would be the use of a
plurality of detents projecting from the inner side of side walls 72 for
engagement with a surface, or recess in a surface, of the trays and/or
bins.
Regardless of the embodiment, several design modifications may also
contribute to easier assembly of the doors 20 and 70, such as the
incorporation of a snap-in gasket 65. A gasket receptacle may be produced
independently of the door and subsequently encapsulated therein during the
second blow molding step (for doors produced according to the first
embodiment) or the gasket receptacle may be formed in the exterior of the
side, bottom and top walls (for doors produced according to the second
embodiment), whereby such easy insertion of the gasket 65 into its
receptacle would obviate the need for timely attachment of gasket 65 using
screws or the like, as previously disclosed. A second modification may
include the formation of an integral door handle in the exterior surface
of door 20 or 70. A vertically disposed handle adjacent one lateral side
of door 20 or 70 would necessitate the production of both left and
right-handed doors. However, a horizontally disposed integral handle
spanning the width of the door would still allow for reversible door
mounting, as previously described. Such a door handle would obviate the
need for mechanically joining a door handle to the exterior surface of the
door.
Several cosmetic design considerations are also available for both
embodiments without the requirement of complex manufacturing steps. For
example, door within door assemblies may be effected using simple mold
set-up procedures, thereby allowing access to individual interior door
compartments without requiring the primary door to be opened. A second
example is the addition of a third door dam or wall insert, either partial
or full-length, for the purpose of creating a greater number of
specialized compartments or shelves. A third example is the placement of a
uniform depth recess of any desired shape, such as rectangular or oval,
etc., in the exterior surface of door slab 21 or 71 for the purpose of
mounting therein a corkboard, erasable message board or the like. This
could be effected in door 20 by using only insert 88 rather than both
inserts 87 and 88. A fourth example is the incorporation of folded
retaining strips with the lateral and bottom edges of the door slab 21 or
71 during the second blow molding step. The addition of the retaining
strips would allow custom fascia retainably to be inserted therebetween
against the exterior surface of the door slab, thereby allowing a
refrigerator decoratively to be coordinated with the kitchen interior into
which it has been placed.
A cold liquid and ice dispenser receptacle, among other functional options,
may also be incorporated into the the access opening 25 in door 20, or in
a recess in the exterior wall of the door, more easily than with
conventional door assemblies. Whereas accommodations for the liquid and
ice dispenser require post production modifications of conventional doors,
the manufacturing process of the present invention allows a housing for
the liquid and ice dispenser to be captured in the exterior door surface
during the second step. Actual installation of the water line and
equipment required for these services would, however, require additional
work and time as is the case with conventional refrigerator doors.
Although this invention has been described in conjunction with certain door
walls 22 and 72, trays 24 and 74 and bridge 26, it should be apparent to
those skilled in the art that alternative design configurations may also
be employed for performing the desired services thereof without departing
from the scope of this invention.
Moreover, while this invention has been described and illustrated with only
certain embodiments thereof, it will be apparent that this invention is
capable of still further modifications, and that this application is
intended to cover any such modifications as may fall within the scope of
one skilled in the art or the appended claims.
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